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Title: Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak

Abstract

We present the first localized measurements of long and intermediate wavelength turbulent density fluctuations ($$\sim\atop{n}$$) and long wavelength turbulent electron temperature fluctuations ($$\sim\atop{T}$$ e) modified by m/n = 2/1 Neoclassical Tearing Mode (NTM) islands (m and n are the poloidal and toroidal mode numbers, respectively). These long and intermediate wavelengths correspond to the expected Ion Temperature Gradient and Trapped Electron Mode scales, respectively. Two regimes have been observed when tracking $$\sim\atop{n}$$ during NTM evolution: (1) small islands are characterized by a steep T e radial profile and turbulence levels comparable to those of the background; (2) large islands have a flat T e profile and reduced turbulence level at the O-point. Radially outside the large island, the T e profile is steeper and the turbulence level increased compared to the no or small island case. Reduced turbulence at the O-point compared to the X-point leads to a 15% modulation of $$\sim\atop{n}$$ 2 across the island that is nearly in phase with the T e modulation. Qualitative comparisons to the GENE non-linear gyrokinetic code are promising with GENE replicating the observed scaling of turbulence modification with island size. Furthermore, these results are significant as they allow the validation of gyrokinetic simulations modeling the interaction of these multi-scale phenomena.

Authors:
 [1];  [1]; ORCiD logo [1];  [1];  [1];  [2];  [3];  [2]; ORCiD logo [2];  [1]
  1. Univ. of California, Los Angeles, CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1372473
Alternate Identifier(s):
OSTI ID: 1348028
Grant/Contract Number:  
FC02-04ER54698; FG02-08ER54984; FG03-86ER53266; SC0016073; AC02-05CH11231; S014889-R
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Turbulent flows; Magnetic islands; Plasma turbulence; Turbulence measurement; Turbulence effects

Citation Formats

Bardoczi, Laszlo, Rhodes, Terry L., Navarro, Alejandro Banon, Sung, Choongki, Carter, Troy A., La Haye, Robert J., McKee, George R., Petty, Clinton C., Chrystal, Colin, and Jenko, F. Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak. United States: N. p., 2017. Web. doi:10.1063/1.4977533.
Bardoczi, Laszlo, Rhodes, Terry L., Navarro, Alejandro Banon, Sung, Choongki, Carter, Troy A., La Haye, Robert J., McKee, George R., Petty, Clinton C., Chrystal, Colin, & Jenko, F. Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak. United States. doi:10.1063/1.4977533.
Bardoczi, Laszlo, Rhodes, Terry L., Navarro, Alejandro Banon, Sung, Choongki, Carter, Troy A., La Haye, Robert J., McKee, George R., Petty, Clinton C., Chrystal, Colin, and Jenko, F. Fri . "Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak". United States. doi:10.1063/1.4977533. https://www.osti.gov/servlets/purl/1372473.
@article{osti_1372473,
title = {Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak},
author = {Bardoczi, Laszlo and Rhodes, Terry L. and Navarro, Alejandro Banon and Sung, Choongki and Carter, Troy A. and La Haye, Robert J. and McKee, George R. and Petty, Clinton C. and Chrystal, Colin and Jenko, F.},
abstractNote = {We present the first localized measurements of long and intermediate wavelength turbulent density fluctuations ($\sim\atop{n}$) and long wavelength turbulent electron temperature fluctuations ($\sim\atop{T}$e) modified by m/n = 2/1 Neoclassical Tearing Mode (NTM) islands (m and n are the poloidal and toroidal mode numbers, respectively). These long and intermediate wavelengths correspond to the expected Ion Temperature Gradient and Trapped Electron Mode scales, respectively. Two regimes have been observed when tracking $\sim\atop{n}$ during NTM evolution: (1) small islands are characterized by a steep Te radial profile and turbulence levels comparable to those of the background; (2) large islands have a flat Te profile and reduced turbulence level at the O-point. Radially outside the large island, the Te profile is steeper and the turbulence level increased compared to the no or small island case. Reduced turbulence at the O-point compared to the X-point leads to a 15% modulation of $\sim\atop{n}$2 across the island that is nearly in phase with the Te modulation. Qualitative comparisons to the GENE non-linear gyrokinetic code are promising with GENE replicating the observed scaling of turbulence modification with island size. Furthermore, these results are significant as they allow the validation of gyrokinetic simulations modeling the interaction of these multi-scale phenomena.},
doi = {10.1063/1.4977533},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Fri Mar 03 00:00:00 EST 2017},
month = {Fri Mar 03 00:00:00 EST 2017}
}

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